Machine gun mechanism



Oct 10, 19.

W. D. D. HAMMOND MACHINE GUN MECHANISM Filed Aug. 11, 17941 2 Sheets-Sheet 2 Patented Oct. 10, 1944 MACHINE GUN MECHANISM William Daniel Douglas Hammond, Los Angeles, Calif., assigner to Machinery Sales Company, Los Angeles, Calif., a corporation of California Application August 11, 1941, Serial No. 406,249

3 Claims.

The machine gun of this invention relates to that division of machine gunsv generally known as sub-machine guns, and has `for its purpose the following provisions, to wit:

" (lst) Extreme simplicity.

(2nd) Low cost of manufacture.

(3rd) A minimum of working parts.

(4th) Reliability of operation.

(5th) Lightnessof weight.

(6th) Maneuverability when ring.

(7th) Portability.

(8th) Ease of repair, and/ or parts replacement.

(9th) To provide Ia ring mechanism for machine guns in which pressures alternately applicable at points tangental to the place of iulcrum in a hammer are adapted to periodically raise the hammer and snap the same upon a firing pin.

(10th) To provide means in a -lring mechanism for a gun to cock the hammer whereby the bolt is able to move in recoil to eliect reloading of the gun, and cam means actuated by return or breech closing movement of the bolt to swing the ham- 'mer past a point of oli" -center Iand through a point of dead-center spring-thrust pressure whereby said spring-thrust pressure forces the hammer upwardly in an ascending movement following the preceding movement of the bolt so that the firing pin is struck just subsequent to the closing of the breech by the said bolt. Y (11th) To provide a firing mechanism in a machine gun wherein a hammer is provided with a spring, the thrust of which in eXtreme positions is applicable in directions tangental -to the fulcrum of the hammer, the hammer being alternately depressible by the bolt of the gun in recoil and being ascendingly motivated by, (a) bolt actuated pressure, followed by, (b) thrust of the 'said spring in one of the directions tangental of the fulcrum of the hammer whereby the hammer is alternately moved to and from ring position. (12th) To provide a firing mechanism for a machine gun, wherein the hammer ofthe gun is depressible by recoil movement oi the bolt of the gun, and which hammer is actuated to ring position by the forces in combination, of bolt actuated means, and, in sequence, spring-thrust pressure means, whereby the hammer is repettiously moved to and from firing position.

Other objects', 'features and advantages of the invention may appear from the accompanying drawings, the specication, and sub-joined claims.

In the drawings:

Figure 1 is a schematic View showing the operating elements involved in the firing mechanism of this invention, the parts being shown in firing position.

Figure'Z is a view of the invention showing the operating parts in recoil position.

Figure 3 is a View of the functional elements of the invention in an intermediate position moving toward firing position.

Figure 4 is a view in section taken along line i-ll of Fig. 1 showing the hammer in raised position and other associated elements of the gun in (zo-operative position.

Figure 5 is a View in section taken along line 5 5 of Fig. 2 showing the bolt actuated cam in position accommodating the depressed hammer, the reversal of this position is adapted to initially start Ythe hammer in its ascending movement toward striking the firing pin.

Figure 6 is a sectional view taken substantially along line 6 6, in Figure 4 showing in particular the means used to shield the trigger actuated bar within the body portion of the gun, the bar being the means used to connect the trigger with the hammer releasing block.

Figure 7 is a side elevation of a portion of the gun body, the View being adapted to show that one of the faces of the body of the gun is detachable, being held in position by any practical means such as screws.

The present invention is concerned only with the mechanical elements necessary to obtain repetitions movement of the hammer to and from position necessary to detonate a cartridge. Such accessories as grips and sheathing for the gun have been entirely eliminated as well as the customary means to automatically load cartridges from a clip or drum, for such adjuncts are within the scope of the accepted art and are in reality, irrelevant to the present invention, and accordingly have not been illustrated.

In the drawings the reference character l0 indicates a body or case within which the several operating elements of the gun are functionable.

Within the body itl, l place a breech bolt I2 which I recess as shown at lli to receive a hammer IS in its necessary movement to and from firing pin striking position.

A.v ring pin i8 is centrally aligned within th bolt l2, being provided with a spring 20 which, bearing against a head 22 upon the iirng pin and against the end wall 24 of a recess within which the head is movable, is adapted to normally urge the iiring pin head into the chamfered portion Iii whereby the firing pin may be actuated by the hammer i6 as will more fully appear as the'speciiication is developed. A pin 2S secured within 'walls 52 and 48.

the bolt and having a free end loosely Iitted within a slot 28 in the pin'I 8 is adapted to limit movement of the firing pin in extremeV directions, while a spring 3U within the body I0 and encircling an extension I2a of the bolt I2, is adapted to not only absorb recoil movement of the boltV butto also force return of the bolt to breech closing position, which movement also forces a cartridge 32 from a clip 34 into the ring chamber 36 of the gun.

The body portion IU is provided or formed with Y a downwardly extending rectangular pocket 38 having one open side which is coverable with a detachable plateV 48 as shown in Figure 7. The

Y hammer I6 is fulcrumed within this rpocket although, as shown in Figures 1, 2, and 4, it swingsY l upon its fulcrum 42 in such manner as to par-- bifurcated, being formed with parallel legs 44 and 46. YA wrist pin 48 extends across the space .loe-V tween the legs 44 and 46`and is suitably connected in a substantially integral manner with a pin 58 the opposite end of which is` movable Yin a tubular member 55 secured upon a second wrist pin 48a, which is journalled inthe wall 52 of the pocket 38 and in the cover' plate 40. A spring 53 surrounds pin 50 and tubular member 55 being under compression to force the'wrist pin 48 upwardly. When the hammer is inA depressed or cocked position the line of action of this spring passes close to the axis of hammer ypivot 42; in the full cocked position of Fig. .2 passing slightly to the left of the pivot, and in the vlatching posil tion of Fig. 3 passing slightly to the right of theV pivot.

54, while the opposite extreme thereof is formed with a lobe 62V which is adapted to be intermittently in striking contact with the end 64 of a :slot 66 formed in the under-side of the bolt I2. The opposite end of the slot .66 is sealed from open connection with the breech by the end wal1 `68. Intermediate portions of the cam 54 are `formed in a constant radius whereby the cam may partially rotate within the slot 66, While a pin 'I0 secured in the Wall portions 48 and 52, and extending through an arcuate slot I2 in the cam, is adapted to form a stop limit of rotation-in the` cam.

Vextension '18, is connected with a bar 80 by means of a slot and pin arrangement 82. As shown in vFigure 6, the pin 84 extends laterallyV of the trigger and is integrally connectedwith the bar v88 which lies within an elongated slot 86 formed Yin the wall 52 ofthe pocket 38. The opposite end of the bar 88 is integrally connected to a block or `sear 88 of such width asto be snugly fitted within and movable within the space defined byY the 88 and extending through the wall 82, is adapted to center a, spring 94which in resisting compres-v `sion naturally tends to throw the trigger 14 into non-functional position.

v The preceding description is believed to cover .the physical detail involved in the structural ar- A trigger 14, fulcrumed at I6 and having an A pin 90, securedk to the block rangement involved in the invention, co-relation of the severalelements therein and a description of operation will now be made.

It will be assumed that the gun has been tired and that the relationship between the hammer I6, the bolt I2,- the cam 54, and particularly including the pin and sleeve elements 50 and 55 respectively, and the spring 53, are in the position shown in Figure 1. Movement of the bolt in recoil will cause the bolt surface I3 to bear against the hammer I 6 so that the hammer will progressively swing upon its fulcrum 42 until it is positioned as shown in Figure 2, the surface 65 of the bolt having slid over the surface I1 of the hammer. degree of resistance oiered by the hammerrto movement is not alone proportional to resistance oiered by the spring 53 to compression, butris more particularly determined by distance between the point of contact between the heel or corner 65a, of the bolt and the axial center, or the fulcrum point 42.V`

The point of application of boltpressure upon throwing the cam into upper-most position so .Y that the lobe 62 is aligned in a rear-ward direction as shown in Figure 2. Upon absorption of pressure of the bolt in recoil, the spring 30 forces the bolt to retrace its movement andin so doing Ythe face 84 strikes the lobe 62 and partially rotat-V ing the cam causes the hammer to be moved in a reverse direction. The. block as shownrin Figure 3, being in trigger pressed advanced position,

, permits free movement'of the hammer and full automatic ring `of the gun for the reason that rthe cam has imparted initial motion to the hammer and has forced the spring pressure point 48 through the line B-C so that the thrust of the previously compressed spring 53 isfree to carry the hammer I6 upwardly through its range of ltravel to strike the firing pin I8. YIf thertrigger is released the sear 88'wi1l be drawn under the extensions 44 and 48 ofthe hammer (Fig. 6) and the latter will be retained in the locking position of Fig. 3. The iirst orinitial movement inthe hammer is obtained as aforestated, by reason of pression of theA spring53 reacts. to throw the hammer upwardly through the remainder orf its course of travel; Y

In like manner, during movement of the bolt in recoil, after the hammer has been forced by recoil pressure past` the center line BC, the line of spring' pressure thrust, switches from the line E-F, to the line 'Gr-H, sothat after a. measure of movement due to recoil ofthe gun,.the re- Ymainder of the retractive movement of the, hammer is elected by pressure ofy thespring 53, thus limiting friction and wear to a minimum as wellv as affording awell balanced movement i'those elements of the gun Vwhich move to and .from

It is to be noted at this point that the Y.

functional position and which by their nature must be relatively heavy and as a consequence possess a considerable degree of inertia.

The preceding matter is descriptive of a cycle of operation of the mechanism of this invention, like or repetitious movement would naturally require repetitious description.

In conclusion it may be stated that various changes and modifications may be made in practicing the invention in departure from the drawings and description as given, without however, departing from the spirit of the invention as defined by the appended claims, which are accordingly to be considered as definitive of the invention.

I claim:

1. A firearm comprising reciprocable breech closing mechanism, a firing pin, a hammer pivoted in position to engage the firing pin when the breech is closed, a hammer spring mechanism having pivotal connection with the hammer with the line of action of the spring passing close to the pivot of the hammer when the latter is in cocked position, a sear adapted to retain the hammer in cocked position with the line of action of the hammer spring passing to that side of the hammer pivot in which the spring tends to move the hammer to firing position, a trigger operative upon pressure to shift the scar, connections between the breech closing mechanism and the hammer operative upon opening of the breech to move the hammer a substantial amount beyond said cocked position, and mechanism actuated by the breech closing mechanism upon closure of the breech to cause the hammer spring to shift the hammer into cocked position to engage the sear if the trigger is not pressed, or to continue rotation into firing position under the action of the hammer spring if the trigger is kept pressed.

2. A firearm comprising a reciprocable breech closing mechanism, a ring pin, a hammer pivoted in position to engage the firing pin when the breech is closed, a hammer spring mechanism having pivotal connection with the hammer with the line of action of the spring passing close to the pivot of the hammer when the latter is in cocked position, connections between the breech closing mechanism and the hammer -operative upon opening of the breech to move the hammer into a position in which the line of action of the hammer spring will pass to that side of the hammer pivot in which the spring tends to move the hammer away from firing position, whereby said spring will temporarily hold the hammer in overcocked position, mechanism actuated by the breech closing mechanism upon closure of the breech to shift the hammer in a direction to cause the line of action of the hammer spring to shift to that side of the hammer pivot in which the spring tends to move the hammer into firing position, a sear adapted to retain the hammer in cocked position when so shifted by the lastnamed mechanism, and a trigger operative upon pressure to shift the Sear to release the hammer.

3. A rearm comprising a reciprocable breech closing mechanism, a firing pin, a hammer pivoted in position to engage the firing pin when the breech is closed and having a striking surface and a portion extending on the opposite side of the pivot from the striking surface, a hammer spring mechanism having pivotal connection with the hammer with the line of action of the spring passing close to the pivot of the hammer when the latter is in cocked position, connections between theI breech closing mechanism and the hammer operative upon opening of the breech to move the hammer into a full-cocked position in which the line of action of the hammer spring will pass to that side of the hammer pivot in which the spring tends to move the hammer away from firing position whereby said spring will temporarily hold the hammer in over-cocked position, a cam 4rotatably mounted in adjacency both to the breech closing mechanism and to the hammer, said cam having a surface engaging the extending portion of the hammer when the latter is in full cocked position and a second surface extending into engagement with the breech closing mechanism, an abutment on the breech closing mechanism operable on closure of the breech to engage and rotate said cam and thereby to cause rotation of the hammer into a latched position in which the line of action of the hammer spring is on that side of the hammer pivot in which the spring tends to move the hammer into firing position, a sear spring-pressed into position to hold the hammer extension in said latched position, and a trigger operative upon pressure to shift the sear to release the hammer.

WILLIAM DANIEL DOUGLAS HAMMOND. 

